Sewing machine



Jan. 25, Y J SCHAAD 2,700,351

' SEWING MACHINE Filed July 23, 1952 INVENTOR 28 JOHN SCI-IAAD,

ATTORNEY United States Patent SEWING MACHINE John Schaad, Long Island City, N. Y., assignor to Waldes Kohinoor, inc, Long Island City, N. Y, a corporation of New York Application July 23, 1952, Serial :No. 300,471

4 Claims. {6. .112-2I6) This invention relates to improvements in sewing machines and more particularly to an improved sewing machine attachment providing a means for diverting metallic and other hard-material elements aflixed to the material on the article being sewn from the ,path .of the needle, thereby to prevent breakage of the needle.

The problem of needle breakage resulting from a sewing machine needle striking hard elements made, for example, of metal and which are carried by the material being sewn has been .a long-standing one, particularly in the garment industry. Such a problem becomes acute in sewing through slide-fastener or so-called zipper closures, as in the operation of sewing the waist band of trousers to the fly portions thereof. As is well known, trouser flies are commonly provided with a :slide fastener or zipper closure consisting of a pair of fastener stringers whose tapes are connected along their .outer edges to the opposite edges of the fly portions, and are provided along their inner edges with rows of oppositely disposed, closely spaced metallic fastener elements. The element-studded tapes usually extend upwardly .into the waist band which is sewn to the tapes by a line of stitches running transversely across the same, whereby the :lower edge of the waist band may function as a top stop for the slider which serves to engage and disengage the oppositely disposed fastener elements, thus to open and close the trouser fly.

In such sewing operation, it .is a matter of sheer accident whether the needle will pass through the .fastener tape in the space between two adjacent fastener elements, or whether it will strike an element aligned therewith. if the needle strikes the element, it may be broken by such engagement.

Stated broadly, the present invention has for a main object to overcome the likelihood of a sewing machine needle striking a fastener element '(or any other hard element carried by the material being sewn) which may be disposed in the line of feed to the needle, through the provision of means functioning to divert said element out of the path of the needle, with the desirable result that the needle will always pass through material to one or the other side of said element and hence cannot strike thereon.

More particularly, the invention aims to provide an attachment fora sewing machine incorporating a member which is arranged slightly in advance of the needle and in the line of feed thereto, and which is so constructed and arranged as to divert a hard element such as a fastener element disposed so as to feed to the needle out of the line of feed thereto, without-in any way 'inter- I fering with the desired sewing operation.

Yet another object of the invention is the provision of a feed dog for a sewing machine incorporating a blade-like member disposed a small distance in advance of and in the line of feed to the reciprocating needle, and which is cooperated with the usual sewing machine feed dog in such manner that, in the raised position of the dog, it projects upwardly through the plane of feed movement of the material being sewn and functions to divert a hard element such as a fastener element carried by the material and which is so positioned that it normally moves into the path of movement of the needle, to one or the other side thereof, whereby the needle may pass through the material without striking such element.

A still further object of the invention is the provision 2,700,35 l Patented Elan. 25, 1955 of an improved feed dog attachment for sewing machines used to sew a line of stitches through an article provided with closely spaced metallic elements such as slidefastener elements, which incorporates means for pushing any one of the fastener elements moving towards the needle, consequent to the feed motion imparted to the article by the feed dog, out of the path of the needle, so that the latter may pass through the article without striking said fastener element.

The above and other objects and features :of advantage of a sewing machine attachment according to the invention will appear from the following detailed description, in which reference is made to the accompanying drawing illustrating the improved attachment and the manner in which it exercises its protective function on .the sewing machine .needle, in which:

Fig. 1 is a plan view of the sewing machine attachment of the present invention illustrated in connection with the sewing of a trouser waist band to one fly portion of trousers, whose fly is adapted to be opened and closed by means of a slide-fastener or zipper-type closure;

Fig. 2 is a section taken along line 22 of Fig. .1; and

Figs. 3 and 4 are detail views of which Fig. 4 illustrates the fastener-element diverting function of the attachment of the invention.

Referring to Figs. 1 and 2, reference numeral 10 designates the usual throat plate inserted .in the work table of a sewing machine, the throat plate being provided, as usual, with slot-like openings 11 and 12 .disposed parallel to one another and symmetrically to opposite sides of the line of stitching to be sewn, and through which extend the serrated arms 13, 14 of a reciprocating feed dog generally designated by the numeral 15. Inasmuch as the means for reciprocating the feed dog 15 is conventional, such has not been illustrated, but it will be understood that the serrated arms 13, 14 thereof are projected through the openings 11 and 12 in manner and direction as to impart a feed motion of the material being sewn to .a needle 16 (Fig. 2) which moves in a reciprocatory path normal to the plane :of the throat plate 10, which latter is provided with a usual needle hole 17.

vAs above indicated, the invention wili be described .in .its application to the sewing of the waist band of trousers to the fly portions thereof and whose Ffly is adapted to be opened and closed by a slide fastener or zipper-type closure of conventional construction. in Fig. '1, reference numeral 20 indicates one fly portion of the trousers, to the .inner edge of which a slide fastener stringer 21 provided along its free edge with closely spaced metallic :fastener elements 22 is secured as by a line of stitches 23 sewn in a prior operation. The trouser waist band 24 is connected to the upper edge :of the fly portion 26 and to the upper end of the stringer tape 21 'by a line of stitches 25 sewn by the needle 16 upon feed motion being imparted to said garment parts in the direction of the arrow (Fig. 1).

.By reference to Fig. 2, the trouser waist band 24 illustratively consists of a strip of suitable material folded longitudinally on itself so as to form upper and under plies, between which the upper end of the stringer 21 is interposed. Hence, upon the line of stitches 25 being sewn across the tape 21 as indicated in Fig. 1., the lower edgeaof the 'waist band may frlnctionas a top stop for the slider (not shown) which engages and disengages the fastener elements of the slide fastener closure, of which one stringer 21 is illustrated, it being understood that the other stringer is carried by the opposite trouser fly portion which has not been illustrated.

With the top end of the stringer 21 extending into the waist band 24, as clearly seen in Fig. 2, it will be observed that one of the uppermost fastener elements may line up with the needle 16; that is to say, it may be disposed in the direct line of feed to said needle, with the result that, as the feed motion of the garment parts proceeds, said one element is brought into the path of the needle. When this condition occurs, the needle may be broken by its engagement with said element.

According to the present invention, this possibility is prevented through the provision of an attachment which functions positively to divert or shift laterally any fastener element disposed in the line of feed to the needle to one or the other side thereof, whereby the needle, instead of striking such an element, may pass harmlessly through the fastener tape without striking it. As illustratively shown, such attachment may take the form of a longitudinally extending upright blade member 28 carried by the feed dog in the space between the serrated arms 13, 14 thereof. As seen in Fig. 1, the blade 28 is disposed in advance of and in the direct line of feed to the needle 16, and it operates in a slot-like opening 29 provided in the throat plate 10. The opening 29 is disposed intermediate the feed-arm openings 11 and 12 in said plate and so that it terminates at its needle end a short distance in advance of the needle opening 17.

Referring to Figs. 2, 3 and 4, it will be seen that the height of the blade member 28 is somewhat greater than that of the serrated arms 13 and 14 of the feed dog 15, so that in the raised position of the dog it projects through the horizontal plane in which the fastener stringer 21 would normally lie. This results in the blade member 28 functioning to bend the tape upwardly out of its normal plane. Preferably the side faces of the blade member converge towards one another, so that its upper edge is shaped and functions as a knife edge.

The operation of the blade member 28 will be seen from a comparison of Figs. 3 and 4 which schematically illustrate the upper end portion of the stringer tape 21 and the fastener elements 22 carried thereby, of which 22a and 22b designate the two uppermost elements which are covered by the waist band 24. In Fig. 3 it will be observed that said uppermost elements 22a and 22b have non-aligned relation with the needle 16. When such a condition exists, the knife edge of the blade member 28 merely engages the under face of the tape in the space between said elements 22a and 22b, without disturbing in any way their non-aligning relation with respect to the needle 16. Hence, as the tape feeds to the needle, the latter may sew a stitch through the tape material between the elements 22a and 22b in the usual manner.

However, and as illustrated in Fig. 4, if one of the uppermost fastener elements, such as the element 22a, is aligned with, i. e. in the direct line of feed to, the needle 16, as would result in the needle striking said element upon the latter arriving beneath the needle, the blade member 28 engages against said element 22a from beneath before it reaches the needle and, consequent to the upper edge of the blade member 28 .being formed as a knife edge, such engagement causes said element 22a to shift or ride to one side or the other of the blade member and hence to a new position out of alignment with the needle. Thus, the element 22a will be pushed or will move of its own accord'to the positions assumed by one of the elements 22a, 22b as seen in Fig. 3 before it reaches the needle 16, with the result that the needle will not strike the same but, instead, may pass through the tape in the small space between said element and the next adjacent element, as with the Fig. 3 condition. Due to the substantial length of the blade member 28 and its movement with the reciprocating feed dog 15, the blade member may engage beneath a recalcitrant or slowto-shift element a plurality of times between its first engagement therewith and the time said element would normally arrive under the needle, thus practically assuring lateral shift of said element consequent to at least one of such engagements.

Without further analysis, it will be appreciated that the invention provides a simple solution to the longstanding problem of needle breakage encountered in sewing through material or articles carrying hard objects such as the metallic elements of a slide fastener or zippertype closure. The blade member 28 is of itself of simple construction and, moreover, may be incorporated into the conventional feed dog employed in sewing machines in a simple and inexpensive manner, either by forming the blade member as an integral part of the feed dog, or as an addendum thereto in the case of existing feed dogs. Moreover, the building of a blade member 23 as herein proposed into the conventional feed dog employed in sewing machines requires no substantial modification of the sewing machine throat plate, since the slot-like opening 29 through which the blade member operates may be formed therein in extremely simple manner.

As many changes could be made in carrying out the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim: I

1. In a sewing machine, the combination of a throat plate provided with a hole for a reciprocating needle and with parallel slots disposed to the sides of the line of feed to the needle, a reciprocating needle vertically aligned with said needle hole, a reciprocating feed dog having arms operating in said slots for imparting feed motion to the material to be sewn, and a longitudinally extending upright blade member carried by said feed dog and being disposed intermediate, its arms and in the direct line of feed to said needle, said blade member operating in a slot in the throat plate disposed in advance of said needle, said blade member having greater vertical height than said arms and being adapted to engage from beneath a metal or other hard-material element carried by the material being sewn and which is disposed in the line of feed to said needle, and consequent to such engagement to shift said element laterally of said line.

2. The combination set forth in claim 1, wherein the side faces of the blade member converge towards one agother whereby said blade member functions as a knife e ge.

3. An attachment for sewing machines for sewing a row of stitches across a length of material having an edge studded with spaced metallic elements, and which includes a reciprocating feed 'dog having spaced parallel arms operating in slot-like openings provided in the sewing machine throat plate for feeding the material to the needle in a direction transversely of its length, said attachment comprising an upright blade member afiixed to said feed dog between said arms and extending through a slot-like opening in saidthroat plate disposed intermediate the openings for the feed dog arms and in advance of the needle opening also provided in said throat plate, said blade member having greater height than said feed dog arms and being adapted to engage beneath any element carried'by the material which is in alignment with the needle and to divert it laterally of said needle.

4. An attachment for sewing machines as set forth in claim 3, wherein the side faces of the blade member converge towards one another whereby said blade member has knife-edge section.

References Cited in the file of this patent UNITED STATES PATENTS Switzerland May 2, 1949 

